A combined depressor for recovering white tungsten from a low-grade tungsten-molybdenum associated ore and a method thereof

Abstract

The application discloses a combined depressor for recovering scheelite from ultra-low-grade tungsten-molybdenum associated ore and a method, the combined depressor comprising sodium humate, sodium mercaptoacetate, ammonium citrate, sodium pyrophosphate, sodium fluosilicate and lead nitrate, and the six kinds of substances are configured into the combined depressor in a proportion of 1:1:(2-5):(1-5):(1-3):(2-5). The application aims at recovering scheelite from low-grade refractory ore, improves the separation effect of scheelite and gangue minerals, improves the scheelite recovery rate and the concentrate grade, and improves the economic benefit.

Description

Technical Field

[0001] This invention relates to the field of tungsten-molybdenum associated mineral processing technology, specifically a combined inhibitor and method for recovering scheelite, an ultra-low grade tungsten-molybdenum associated mineral. Background Technology

[0002] The main ore type of tungsten-molybdenum associated deposits is aragonite-type, with minor ores being skarn-type, wollastonite-type, and diopside plagioclase-type. The main minerals are scheelite and molybdenite, while gangue minerals include pyrite, chalcopyrite, wollastonite, garnet, pyroxene, quartz, calcite, fluorite, feldspar, mica, apatite, chlorite, and talc.

[0003] Scheelite deposits are associated with calcium-bearing gangue minerals, which have similar floatability and are difficult to separate. The process of recovering scheelite from tungsten-molybdenum associated deposits involves selective flotation of molybdenum followed by scheelite recovery. In this process, the required grinding fineness for molybdenum is relatively low (50-55%), while the scheelite is under-ground (requiring 70%). This results in a high content of coarse-grained minerals in the scheelite concentrate. In the existing process (roughing-heating-cleansing), these coarse-grained minerals are difficult to float in the cleaning stage, leading to metal loss and poor economic efficiency.

[0004] The invention patent with publication number CN111841899A discloses a low-temperature separation method for low-grade tungsten-molybdenum ore using a combined scheelite collector and separation method. The separation method includes: (1) scheelite roughing: using soda ash as an adjuster, the pH of the slurry is adjusted to 10-11; medium-modulus water glass is added to inhibit calcium-containing gangue minerals, and then collector FX-6 is added, followed by one roughing and two scavenging processes to obtain scheelite rough concentrate; (2) Slurry conditioning and refining: the scheelite rough concentrate is concentrated to 70% by mass, stirred and heated to 88 degrees Celsius, then a combination inhibitor of low-modulus water glass and aluminum sulfate is added and kept at that temperature for half an hour, and then diluted to 30% by mass concentration; (3) Refining: the diluted scheelite rough concentrate is refined through a one-roughing, two-refining, and three-scavenging process to obtain scheelite concentrate. However, its scheelite recovery rate is still not high, not exceeding 90%. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a combined inhibitor and method for recovering scheelite from ultra-low-grade tungsten-molybdenum associated minerals. Targeting the recovery of scheelite from low-grade and difficult-to-process ores, this invention improves the separation effect between scheelite and gangue minerals, thereby increasing the scheelite recovery rate and concentrate grade, and enhancing economic benefits.

[0006] To achieve the above objectives, the specific solution adopted by the present invention is as follows:

[0007] A combined inhibitor for the recovery of scheelite, an associated tungsten-molybdenum mineral of ultra-low grade, is provided. The combined inhibitor is composed of sodium humate, sodium mercaptoacetate, ammonium citrate, sodium pyrophosphate, sodium fluorosilicate, and lead nitrate in a mass ratio of 1:1:(2-5):(1-5):(1-3):(2-5).

[0008] As a preferred option, the preparation method of this combination inhibitor is as follows: weigh each raw material according to the proportion, first mix sodium humate, sodium mercaptoacetate, ammonium citrate, sodium pyrophosphate and sodium fluorosilicate evenly, then add lead nitrate and mix evenly again.

[0009] A method for recovering scheelite, a by-product of ultra-low grade tungsten and molybdenum mining, mainly includes the following steps:

[0010] S1. Add sodium carbonate to the molybdenum tailings slurry with a concentration of 35% to 45% to adjust the pH of the slurry to 10-11.

[0011] S2. Add the combined inhibitor for scheelite recovery, stir evenly, then add the collector, and perform one roughing, two scavenging and one pre-selection to obtain rough concentrate 1. Put rough concentrate 1 into a shaking table for separation to produce coarse-grained scheelite middlings 1.

[0012] S3. Concentrate the tailings from the shaking table to a mass concentration of 70% to obtain rough concentrate 2. Heat it to 70°C and stir. Add water glass and aluminum sulfate. Continue heating to 88°C. Add the collector, stir evenly, and keep warm for 1 hour. Then dilute it to a mass concentration of 30%.

[0013] S4. The rough concentrate 2 processed in step S3 is subjected to one roughing, two cleaning and three scavenging processes to obtain scheelite middlings 2.

[0014] S5. Mix the scheelite intermediate ore 1 obtained in step S2 and the scheelite intermediate ore 2 obtained in step S4, concentrate to a mass concentration of 40%, add concentrated hydrochloric acid, stir evenly, let it settle naturally, release the clear water from the top layer after settling, add water to adjust the concentration to 50%, stir evenly, let it settle naturally, release the clear water from the top layer after settling, wash away the residual hydrochloric acid, and finally obtain scheelite concentrate.

[0015] As a preferred option, in step S2, the roughing and pre-cleaning flotation equipment uses a flotation machine, and the sweeping equipment uses a flotation column.

[0016] As a preferred option, diesel engine oil needs to be added during the first and third sweeps in step S4.

[0017] As a preferred option, the collector used in steps S2 and S3 is FX-6.

[0018] At pH 10-11, sodium humate effectively inhibits pyrite and calcite, sodium mercaptoacetate effectively inhibits pyrite and chalcopyrite, and ammonium citrate inhibits calcite, quartz, and fluorite. Sodium pyrophosphate hydrolyzes preferentially to form soluble complexes with calcium ions on the surface of calcite, fluorite, and apatite minerals. Sodium fluorosilicate preferentially desorbs FX-6 from the surface of gangue minerals, while spruce minerals on the surface remain undesorbed. Sodium fluorosilicate hydrolyzes in water to generate silica globules that are suspended in the slurry, inhibiting silica minerals such as quartz and wollastonite. Lead nitrate hydrolyzes under these pH conditions, which can activate scheelite to some extent, inhibit the adsorption of collector FX-6 on gangue minerals, and enhance the inhibitory effect.

[0019] Beneficial effects:

[0020] 1) The combined inhibitor of the present invention contains lead nitrate. Lead nitrate hydrolysis can activate scheelite to a certain extent and inhibit the adsorption of FX-6 on gangue minerals. It can also produce metal chelates with organic acids such as ammonium citrate and sodium humate to enhance the inhibitory effect of the inhibitor components.

[0021] 2) This invention adopts a process of first classifying the coarse concentrate on a shaking table and then heating and refining it, so as to preferentially separate the coarse particles that are difficult to float in the heating and refining process.

[0022] 3) After shaking table classification, the particles entering the cleaning stage are too fine, resulting in poor flotation separation and low concentrate grade and recovery rate. This invention adds diesel engine oil to the first and third cleaning stages. The diesel engine oil effectively adjusts the foam structure, changes foam viscosity and elasticity, causing fine scheelite particles to agglomerate, enhancing the hydrophobicity of the agglomerated scheelite, and improving the separation of scheelite from gangue. It also adjusts the relationship between collector FX-6 and the surface of scheelite and gangue minerals, improving the selectivity of the flotation process. This, in turn, improves the scheelite recovery rate and concentrate grade.

[0023] 4) Apatite and scheelite have similar floatability and are enriched in concentrate. This invention performs acid washing to remove phosphorus and can also remove other gangue minerals that can react with hydrochloric acid and dissolve in water, effectively increasing the grade of scheelite by 5-10 percentage points. Attached Figure Description

[0024] Figure 1 This is a flow chart of the sorting process in this invention.

[0025] Figure 2 The process flow diagram is shown in Comparative Example 10. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0027] This invention discloses a combined inhibitor for the recovery of scheelite, an associated tungsten-molybdenum mineral, which is composed of sodium humate, sodium mercaptoacetate, ammonium citrate, sodium pyrophosphate, sodium fluorosilicate, and lead nitrate. The above six substances are configured into a combined inhibitor in a ratio of 1:1:(2-5):(1-5):(1-3):(2-5).

[0028] The preparation method of this combination inhibitor is as follows: weigh each raw material according to the proportion, mix sodium humate, sodium mercaptoacetate, ammonium citrate, sodium pyrophosphate and sodium fluorosilicate evenly, then add lead nitrate and mix evenly again.

[0029] Another aspect of this invention discloses a method for recovering scheelite, a by-product of tungsten and molybdenum mining. Please refer to [reference needed]. Figure 1 The main steps include: 1. Add sodium carbonate to molybdenum tailings (mass concentration 35%-45%) to adjust the slurry pH to 10-11, add a combined depressant, stir for 5 minutes, add collector FX-6, and perform 1 roughing, 2 scavenging, and 1 pre-cleaning to obtain rough concentrate 1 (where the roughing and pre-cleaning flotation equipment uses a flotation machine, which can effectively recover the coarser particles, and the scavenging equipment uses a flotation column); 2. The rough concentrate enters a shaking table for separation to produce coarse-grained scheelite middlings 1, and the tailings are concentrated to a mass concentration of 70% to obtain rough concentrate 2, which is heated and stirred to 70 degrees Celsius, and depressants water glass and aluminum sulfate are added. The temperature is further increased to 88 degrees Celsius, a small amount of FX-6 is added, and the mixture is stirred and kept warm for 1 hour, and then diluted to a mass concentration of 30%. The diluted slurry enters the beneficiation process and undergoes a three-stage process (using flotation columns) to obtain scheelite middlings 2. In the first stage of flotation, diesel engine oil is added. This oil effectively regulates the foam structure, alters its viscosity and elasticity, causing fine scheelite particles to agglomerate, enhancing the hydrophobicity of the agglomerated scheelite, and improving the separation of scheelite from gangue. It also adjusts the relationship between collector FX-6 and the surface of scheelite and gangue minerals, improving the selectivity of the flotation process. In the third stage, diesel engine oil is added (after the first and second stages of flotation, the oil content in the slurry decreases with foam production, so the oil concentration in the slurry is replenished to a suitable range). Scheelite middlings 1 and 2 are mixed and concentrated to a 40% mass concentration. Concentrated hydrochloric acid is added, and the mixture is stirred until homogeneous. After natural settling, the upper layer of clarified water is released, and water is added to adjust the concentration to 50%. The mixture is stirred until homogeneous, and after natural settling, the upper layer of clarified water is released to wash away residual hydrochloric acid, ultimately yielding scheelite concentrate.

[0030] The technical solution of the present invention will be described in detail below with reference to specific embodiments. It should be noted that the reagent data used in the following embodiments are calculated per ton of raw ore or per ton of rough concentrate.

[0031] Example 1

[0032] The main chemical composition of the molybdenum tailings in this embodiment (mainly argillaceous kerite, including diopside plagioclase kerite, diopside garnet skarn type, epidote, wollastonite, etc.) is shown in Table 1.

[0033] Table 1. Main chemical components of the molybdenum tailings used in Example 1

[0034] Element <![CDATA[WO3]]> <![CDATA[CaF2]]> <![CDATA[NaO2]]> MgO <![CDATA[Al2O3]]> <![CDATA[SiO2]]> P content / % 0.0724 3.24 1.59 2.83 8.88 48.31 0.207 Element S K CaO Ti Mn FeO Zn content / % 0.58 0.89 21.9 0.24 0.89 4.49 0.025 Element Rb Sr Y Zr Mo content / % 0.002 0.01 / 0.074 0.024

[0035] The method for recovering scheelite from tungsten-molybdenum associated minerals in this embodiment is as follows:

[0036] S1. Select the molybdenum tailings with the composition shown in Table 1 (mass concentration 35%-45%) and add sodium carbonate to adjust the pH of the slurry to 10.5;

[0037] S2. Add the combined inhibitor, stir for 5 minutes, add the collector FX-6, and perform 1 coarse, 2 scavenging and 1 pre-cleaning to obtain rough concentrate 1; the rough concentrate is then fed into a shaking table for separation to produce coarse-grained scheelite middlings 1.

[0038] S3. Concentrate the tailings from the shaking table to a mass concentration of 70% to obtain rough concentrate 2. Heat it to 70°C and stir. Add water glass and aluminum sulfate. Continue heating to 88°C. Add the collector, stir evenly, and keep warm for 1 hour. Then dilute it to a mass concentration of 30%.

[0039] S4. The rough concentrate 2 processed in step S3 is subjected to one roughing, two cleaning and three scavenging processes to obtain scheelite middlings 2; diesel engine oil needs to be added in the first and third scavenging processes.

[0040] S5. Mix the scheelite intermediate ore 1 obtained in step S2 and the scheelite intermediate ore 2 obtained in step S4, concentrate to a mass concentration of 40%, add concentrated hydrochloric acid, stir evenly, let it settle naturally, release the clear water from the top layer after settling, add water to adjust the concentration to 50%, stir evenly, let it settle naturally, release the clear water from the top layer after settling, wash away the residual hydrochloric acid, and finally obtain scheelite concentrate.

[0041] Example 2

[0042] The main chemical composition of the molybdenum tailings in this embodiment (mainly argillaceous hornblende, including diopside plagioclase hornblende, diopside garnet skarn type, etc.) is shown in Table 2.

[0043] Table 2. Main chemical components of the molybdenum tailings used in Example 2

[0044]

[0045]

[0046] Compared with Example 1, the only difference in this embodiment is the composition of the selected molybdenum tailings; the sorting process for the tungsten-molybdenum associated minerals is the same as in Example 1.

[0047] Example 3

[0048] The main chemical components of the molybdenum tailings are mainly felsic hornblende, including diopside plagioclase hornblende, diopside garnet skarn, etc.

[0049] Table 3. Main chemical components of the molybdenum tailings used in Example 3

[0050] Element <![CDATA[WO3]]> <![CDATA[CaF2]]> <![CDATA[NaO2]]> MgO <![CDATA[Al2O3]]> <![CDATA[SiO2]]> P content / % 0.0583 1.05 1.6 2.57 9.5 56.6 0.254 Element S K CaO Ti Mn FeO Zn content / % 0.76 2.17 13.31 0.21 0.36 4.01 0.042 Element Rb Sr Y Zr Mo content / % 0.015 0.006 / 0.072 0.016

[0051] Compared with Example 1, the only difference in this embodiment is the composition of the selected molybdenum tailings; the sorting process for the tungsten-molybdenum associated minerals is the same as in Example 1.

[0052] Example 4

[0053] The main chemical components of the molybdenum tailings are mainly felsic hornblende, including diopside plagioclase hornblende, diopside garnet skarn, etc.

[0054] Table 4. Main chemical components of the molybdenum tailings used in Example 4

[0055] Element <![CDATA[WO3]]> <![CDATA[CaF2]]> <![CDATA[NaO2]]> MgO <![CDATA[Al2O3]]> <![CDATA[SiO2]]> P content / % 0.0499 1.05 1.6 2.57 9.5 57.6 0.054 Element S K CaO Ti Mn FeO Zn content / % 0.76 2.17 13.31 0.21 0.56 4.01 0.042 Element Rb Sr Y Zr Mo content / % 0.015 0.006 / 0.072 0.018

[0056] Compared with Example 1, the only difference in this embodiment is the composition of the selected molybdenum tailings; the sorting process for the tungsten-molybdenum associated minerals is the same as in Example 1.

[0057] Comparative Example 1

[0058] The only difference between Comparative Example 1 and Example 1 is that, in step S2, water glass is used instead of the combined inhibitor.

[0059] Comparative Example 2

[0060] The only difference between Comparative Example 2 and Example 2 is that, in step S2, water glass is used instead of the combined inhibitor.

[0061] Comparative Example 3

[0062] The only difference between Comparative Example 3 and Example 3 is that, in step S2, water glass was used instead of the combined inhibitor.

[0063] Comparative Example 4

[0064] The only difference between Comparative Example 4 and Example 1 is that diesel engine oil is not added in step S4 during the sweeping process.

[0065] Comparative Example 5

[0066] The only difference between Comparative Example 5 and Example 2 is that diesel engine oil is not added in step S4 during the sweeping process.

[0067] Comparative Example 6

[0068] The only difference between Comparative Example 6 and Example 3 is that diesel engine oil is not added in step S4 during the sweeping process.

[0069] Comparative Example 7

[0070] The only difference between Comparative Example 7 and Example 1 is that, in step S5, concentrated hydrochloric acid is not added and the mixture is stirred for 5 minutes.

[0071] Comparative Example 8

[0072] The only difference between Comparative Example 8 and Example 2 is that, in step S4, concentrated hydrochloric acid is not added and the mixture is stirred for 5 minutes.

[0073] Comparative Example 9

[0074] The only difference between Comparative Example 9 and Example 3 is that, in step S4, concentrated hydrochloric acid is not added and the mixture is stirred for 5 minutes.

[0075] Comparative Example 10

[0076] The only difference between Comparative Example 10 and Example 4 is that the sorting process used in Comparative Example 10 is the Petrov process, and its process flow is as follows: Figure 2 As shown.

[0077] Effect Example

[0078] (1) Comparative analysis of the present invention and the Petrov method

[0079] Table 5 Results of Example 4 and Comparative Example 10

[0080] Ore grade (%) Scheelite concentrate grade (%) Overall process recovery rate (%) Example 4 0.0499 28.48 80.25 Comparative Example 10 0.0499 18.74 68.81

[0081] As shown in Table 5, the scheelite concentrate obtained by using the separation process of the present invention has a higher grade and a higher overall process recovery rate.

[0082] (2) Analysis of the effects of combination inhibitors

[0083] Table 6 Results of Examples 1-3 and Comparative Examples 1-3

[0084]

[0085]

[0086] As shown in Table 6, the combined inhibitor can effectively increase the enrichment ratio of rough concentrate from about 15 times to more than 20 times while maintaining a slight decrease in recovery rate.

[0087] (3) Analysis of Diesel Engine Oil Effects

[0088] Table 7 Results of Examples 1-3 and Comparative Examples 4-6

[0089]

[0090] Diesel engine oil can adjust the foam structure and agglomerate fine scheelite particles, thereby improving the selectivity of the scheelite flotation process. As shown in Table 7, it can not only improve the recovery rate but also improve the concentrate grade.

[0091] (3) Analysis of pickling effect

[0092] Table 8 Results of Examples 1-3 and Comparative Examples 7-9

[0093]

[0094]

[0095] Calcium-containing minerals such as apatite and quartz have similar floatability to scheelite and are enriched in the concentrate. By utilizing the mechanism of hydrochloric acid reacting with apatite and calcium carbonate to produce soluble salts, impurities in the concentrate are washed away, effectively increasing the grade of scheelite by 5-10 percentage points.

[0096] Therefore, in this invention, the combined inhibitor can effectively improve the grade of rough concentrate while maintaining the recovery rate. Adding diesel engine oil during scheelite beneficiation can effectively improve the separation effect of scheelite and gangue, improve the beneficiation recovery rate and concentrate grade. Adding concentrated hydrochloric acid to the concentrate can effectively remove apatite and calcium carbonate minerals, thereby improving the grade of scheelite concentrate.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention in any way. All equivalent transformations or modifications made in accordance with the essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for recovering scheelite, a by-product of ultra-low-grade tungsten and molybdenum mining, characterized in that, The main steps include the following: S1. Add sodium carbonate to the molybdenum tailings slurry with a concentration of 35%~45% to adjust the pH of the slurry to 10-11. S2. Add the combined inhibitor, stir evenly, then add the collector, and perform one roughing, two scavenging and one pre-cleaning to obtain rough concentrate 1. The rough concentrate 1 is then fed into a shaking table for separation to produce coarse-grained scheelite middlings 1. The combined inhibitor is composed of sodium humate, sodium mercaptoacetate, ammonium citrate, sodium pyrophosphate, sodium fluorosilicate and lead nitrate in a mass ratio of 1:1:(2-5):(1-5):(1-3):(2-5). S3. Concentrate the tailings from the shaking table to a mass concentration of 70% to obtain rough concentrate 2. Heat it to 70°C and stir. Add water glass and aluminum sulfate. Continue heating to 88°C. Add the collector, stir evenly, and keep warm for 1 hour. Then dilute it to a mass concentration of 30%. S4. The rough concentrate 2 processed in step S3 is subjected to one roughing, two cleaning and three scavenging processes to obtain scheelite middlings 2. S5. Mix the scheelite intermediate ore 1 obtained in step S2 and the scheelite intermediate ore 2 obtained in step S4, concentrate to a mass concentration of 40%, add concentrated hydrochloric acid, stir evenly, and let it settle naturally. After settling, release the clear water from the top layer, add water to adjust the concentration to 50%, stir evenly, and let it settle naturally. After settling, release the clear water from the top layer to wash away the residual hydrochloric acid, and finally obtain scheelite concentrate.

2. The method for recovering scheelite, a by-product of tungsten and molybdenum mining, according to claim 1, is characterized in that... The preparation method of this combination inhibitor is as follows: weigh each raw material according to the proportion, first mix sodium humate, sodium mercaptoacetate, ammonium citrate, sodium pyrophosphate and sodium fluorosilicate evenly, then add lead nitrate and mix evenly again.

3. The method for recovering scheelite, a by-product of ultra-low grade tungsten and molybdenum mining, according to claim 1, is characterized in that... In step S2, flotation machines are used for roughing and pre-cleaning flotation, and flotation columns are used for scavenging.

4. The method for recovering scheelite, a by-product of tungsten and molybdenum mining, according to claim 1, is characterized in that... In step S4, diesel engine oil needs to be added during the first and third sweeps.

5. The method for recovering scheelite, a by-product of ultra-low grade tungsten and molybdenum mining, according to claim 1, is characterized in that... In steps S2 and S3, the collector used is FX-6.

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